Neutrons produced by 1.22 GeV antiproton interactions with nuclei

Inclusive neutron energy spectra were measured by time of flight using 1.22 GeV antiprotons from LEAR, CERN, as projectiles and targets from natural Al, Cu, Ag, Ho, Ta, Au, Pb, Bi, U. The sum of two Maxwellian distributions was fitted to the spectra obtained at several forward and backward angles yielding neutron multiplicities M_i and slope or temperature parameters T _i for the low-energy (evaporative, i=1) and high-energy (pre-equilibrium,i=2) parts, respectively. M ₁ increases with A, proportional to the nuclear volume, and M ₂ is growing with A , proportional to the nuclear radius. The T parameters are nearly independent of A. The results are compared with previous multiplicity measurements with a neutron detector, intranuclear cascade calculations and neutron spectra from stopped antiproton annihilation on nuclei. With the measured proton spectra also the ratio of emitted neutrons to protons was determined for Au. Received: 25 February 2000 / Accepted: 19 May 2000     

Time-of-flight studies of emission of μt from frozen hydrogen films

In recent TRIUMF experiments, a μ^- beam is stopped in a solid hydrogen film with a small fraction of T₂. The Ramsauer-Townsend (RT) mechanism allows μt to escape into vacuum with a few eV of energy. To study the emission process, an imaging system was used to determine the position of muon decays. Experimental histograms are in good agreement with a Monte Carlo simulation. This revised version was published online in August 2006 with corrections to the Cover Date.     

Resonant formation measurements of dt\mu via time of flight

Solid hydrogen in the form of an inhomogeneous layered target offers several experimental advantages when compared with liquid or gas. Beams of non-thermalized muonic hydrogen atoms allow us to explore resonant molecular ion formation processes near eV kinetic energies. Isotopically specific layers make it possible to separate competing and confusing interactions and to employ the time of flight for comparison with predictions based on theoretical energy dependences. Unambiguous charged fusion product detection simplifies absolute intensity measurements. The systematic uncertainties encountered in resonant molecular ion formation measurements, using solid hydrogen target layers, are being investigated with simulations which use the many calculated energy-dependent rates and cross-sections which are now available. The importance of the rates for processes such as muon transfer and elastic scattering are discussed, and results of some recent analyses are presented. This revised version was published online in August 2006 with corrections to the Cover Date.     

Detection of Catalytic Activity in Combinatorial Libraries of Heterogeneous Catalysts by IR Thermography

Only about 200 μg of catalyst are required to identify the catalytically active materials on a combinatorial library of heterogeneous catalysts by IR thermography. The procedure is highly sensitive, and temperature differences arising from catalytic activity of hydrogenations and oxidations have been reliably detected down to 0.1 K.     

A double-frequency solid-state laser on organic compounds

A double-frequency narrow-band tunable laser with a solid-state organic active medium pumped by the 2nd harmonic of a YAG–Nd³⁺ laser has been developed. The laser emits in the range from uv (with frequency doubling) to near ir wavelengths. The energy and lifetime characteristics of the laser suffice for its practical applications. It can be used as a master oscillator for a high-power narrow-band solid-state laser on organic compounds.